Forty-eight hours — two full days. Enter when your fast starts and see exactly when it ends, with guidance for the stretch past 24 hours.
Your 48-hour fast ends —
Safety: Extended fasts deserve respect: electrolytes past 24h, stop at dizziness/nausea/racing heart. Not for pregnancy, eating-disorder history, or without medical guidance if you take glucose-affecting medication.
Past the 24-hour mark: electrolytes stop being optional. Water plus salt (or an electrolyte mix) through day two — headaches on extended fasts are usually salt, not willpower.
Refeeding after 48 hours: start small and light, wait an hour, then eat normally. Two days without food means your gut wants a gentle re-entry, not a feast.
Drink to thirst plus a baseline — most people do well on 2–3 liters a day with electrolytes. Dark urine means drink more.
Light movement is fine; hard training can wait. Day two is for walking, not PRs.
Dizziness, nausea, heart racing, or just feeling wrong. Ending early is a good decision, not a failed fast.
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Open in Fluent Fast →More calculators: 16:8 · 18:6 · 20:4 · OMAD · Fast end time · Eating window
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